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Holocene paleohydrology and paleoclimate at treeline, North-Central Russia, inferred from oxygen isotope records in lake sediment cellulose

Holocene paleohydrology and paleoclimate at treeline, North-Central Russia, inferred from oxygen isotope records in lake sediment cellulose
The AA. use lake-water oxygen-isotope histories, inferred from stratigraphic analysis of cellulose in the fine-grained fraction of lake-sediment cores, to reconstruct Holocene paleohydrology at the boreal treeline near the lower Yenisey and Lena
Rivers of northern Russia. These studies are supplemented by isotopic analysis of samples of modern meteoric water, including precipitation, groundwater, and ground-ice, which provide insight into the modern isotope hydrology. The isotopic records

Late Quaternary climate and hydrology of tropical South America inferred from an isotopic and chemical model of Lake Titicaca, Bolivia and Peru

Late Quaternary climate and hydrology of tropical South America inferred from an isotopic and chemical model of Lake Titicaca, Bolivia and Peru
Bolivia ; Climatic variation ; Geochemistry ; Isotope analysis ; Lake ; Lake level ; Model ; Oxygen 18 ; Palaeoclimate ; Palaeohydrology ; Peru ; Quaternary ; Salinity ; South America ; Tropical zone
A simple mass balance model provides insight into the hydrologic, isotopic, and chemical responses of Lake Titicaca to past climatic changes. Latest Pleistocene climate of the Altiplano is assumed to have been 20% wetter and 5°C colder than today
, based on previous modelling. The simulation of lacustrine change since 15,000 cal yr B.P. is forced by these modeled climate changes. Here the AA. employ an isotopic and chemical model in order to assess the magnitude of hydrologic changes required
to produce the observed lake-level changes and to investigate the expected isotopic and chemical response of the lake to water balance changes.

Oxygen-isotope analyses and Pleistocene ice volumes

Oxygen-isotope analyses and Pleistocene ice volumes
The oxygen-isotope record from fossil foraminifera in deep-sea sediments is commonly used as a proxy for global ice volume. The linkage between O and ice volume, however, is probably nonlinear. The AA. have developed a simple numerical model
of the isotopic response of the oceans to ice-volume change. They illustrate the response of their model to simple hypothetical ice-volume transitions of ice growth and ice decay. Sensitivity tests are illustrated for all model parameters. The results suggest
that oxygen-isotope records reproduce the general patterns on ice-volume change fairly accurately. The foraminiferal isotope record, however, may misrepresent the true amplitude of the ice-volume signal and lag true ice volume by 1000 to 3000 yr.

Strontium isotopes as indicators of mineral weathering in catchments

Strontium isotopes as indicators of mineral weathering in catchments
out in the use of strontium isotopes in mineral weathering studies.

Strontium isotopes in trees as an indicator for calcium availability

Strontium isotopes in trees as an indicator for calcium availability
Preliminary analyses of water (precipitation, throughfall, runoff, soil-water), soil (mineral matter) and biological material (trees, musselshells) show that the use of the strontium isotope ratio 87 Sr/86Sr is a powerful tool in estimating

New isotopic and sedimentological measurements of the Thabaseek deposits (South Africa) and the dating of the Taung hominid

New isotopic and sedimentological measurements of the Thabaseek deposits (South Africa) and the dating of the Taung hominid
Archeological site ; Cape Province ; Dating ; Geochemistry ; Isotope dating ; Quaternary ; Sedimentology ; South Africa ; Stratigraphy

Pleistocene paleoclimate of the arid region of Israel as recorded in calcite deposits along regional transverse faults and in veins

Carbone ; Domaine aride ; Géochimie ; Isotope ; Israël ; Negev ; Oxygène 18 ; Paléoclimat ; Paléoclimatologie ; Pléistocène ; Quaternaire
Arid land;Arid environment ; Carbon ; Geochemistry ; Isotope ; Israel ; Negev ; Oxygen 18 ; Paleoclimate ; Paleoclimatology ; Pleistocene ; Quaternary
The AA. use the carbon and oxygen isotopic composition of the calcites to study the climatic record and mode of formation of speleothem deposits.

Monsoon fluctuations in two 20,000-yr B.P. Oxygen-isotope/pollen records off southwest India

Monsoon fluctuations in two 20,000-yr B.P. Oxygen-isotope/pollen records off southwest India
Carotte océanique ; Géographie physique ; Holocène ; Inde ; Isotopes de l'oxygène ; Mousson ; Palynologie ; Paléoclimatologie ; Pléistocène supérieur ; Quaternaire zone chaude ; Variation climatique

Information about the origin of thermomineral waters and gas by means of environmental isotopes in eastern Azerbaijan, Iran, and southeast France in Hydrogeothermal studies. 26th International geological congress.

Information about the origin of thermomineral waters and gas by means of environmental isotopes in eastern Azerbaijan, Iran, and southeast France in Hydrogeothermal studies. 26th International geological congress.
Azarbaïjan ; Deutérium-Oxygène 18 ; Eau météorique ; Eau souterraine ; Eau thermominérale ; France ; France du Sud-Est ; Géographie physique ; Hydrogéologie ; Hydrothermal ; Iran ; Isotope ; Recharge naturelle ; Source ; Tritium ; Volcanisme

Isotopic identification of gases of a deep origin in French thermomineral waters in Hydrogeothermal studies. 26th International geological congress.

Isotopic identification of gases of a deep origin in French thermomineral waters in Hydrogeothermal studies. 26th International geological congress.
Deutérium/Oxygène 18 ; Eau juvénile ; Eau météorique ; Eau souterraine ; Eau thermominérale ; France ; Géographie physique ; Hydrothermal ; Isotope ; Massif Central ; Source ; Volcanisme

Quelques remarques pratiques et une représentation commode facilitant l'exploitation des variations naturelles en deutérium et en oxygène-18 dans les eaux

Deutérium ; Eau ; Géographie physique ; Hydrochimie ; Hydrométrie ; Isotope ; Oxygène 18
This note recommends to hydrologists and hydrogeologists a new method of presentation of natural isotopic contents of waters. That may contribute to easier interpretation of such measurements. It is illustrated with two examples of recent isotopic

Oxygen and strontium isotope relationships in the British late Caledonian granites

Oxygen and strontium isotope relationships in the British late Caledonian granites
Oxygen and strontium isotope data for 25late Caledonian granite plutons emplaced between 435and 390Myr indicate that the parent magmas were hybrids, derived from partial fusion of mantle-like material and varying proportions of a crustal component.

Evolution of isotopic composition and concentration of atmospheric CO2 as result of anthropogenic influences

Evolution of isotopic composition and concentration of atmospheric CO2 as result of anthropogenic influences
Atmosphere ; Carbon dioxide ; Cracow ; Geochemistry ; Human impact ; Isotope analysis ; Poland ; Pollution ; Town
Systematic investigations of the isotopic composition in atmospheric CO2 and its concentration in Cracow urban area have been carried on. Continuous sampling at biweekly intervals was supplemented by series of samples representing four-hour periods

Strontium isotope ratios in streams and the effect of flow rate in relation to weathering in catchments

Strontium isotope ratios in streams and the effect of flow rate in relation to weathering in catchments
Discharge ; Geochemistry ; Isotope analysis ; Scotland ; Strontium ; Tracer ; United Kingdom ; Water erosion ; Watershed ; Weathering
To provide more detail information on the effect of flow rate on strontium isotope ratios, the Sr 87/Sr 86 ratio was measured in streamwater samples taken at low and high flow rates and also in samples taken at four and eight hourly intervals during

Laurentide ice sheet extent inferred from stable isotopic composition (O, C) of ostracodes at Toronto, Canada

Laurentide ice sheet extent inferred from stable isotopic composition (O, C) of ostracodes at Toronto, Canada
The data of this paper show the potential for using isotopic analyses of ostracodes to learn about the isotopic composition of terrestrial meltwater from the Laurentide Ice Sheet. These midcontinent data are especially valuable because they help

Spatial distributions of organic carbon and nitrogen and their isotopic compositions in sediments of the Changjiang Estuary and its adjacent sea area

Spatial distributions of organic carbon and nitrogen and their isotopic compositions in sediments of the Changjiang Estuary and its adjacent sea area
Carbon ; China ; Coastal sedimentation ; Estuary ; Geochemistry ; Isotope analysis ; Jiangsu ; Nitrogen ; Organic materials ; Spatial distribution
The spatial distribution patterns of total organic carbon and total nitrogen show significant correlations with currents of the East China Sea Shelf. The purposes of this paper are to analyze characteristics of stable carbon and nitrogen isotopes

Phytolith and carbon isotope evidence for late Quaternary vegetation and climate change in the Southern Black Hills, South Dakota

Phytolith and carbon isotope evidence for late Quaternary vegetation and climate change in the Southern Black Hills, South Dakota
C 14 dating ; Carbon ; Climatic variation ; Grassland ; Holocene ; Isotope analysis ; Palaeobiogeography ; Quaternary ; South Dakota ; United States of America ; Vegetation
Analyses of phytoliths and carbon isotopes document the rate and nature change in late Quaternary grasslands in the Red Valley of the southern Black Hills. This paper will evaluate the temporal sensitivity and spatial limits of the methods.

Strontium isotope ages of the marine Merced Formation, near San Francisco, California

Strontium isotope ages of the marine Merced Formation, near San Francisco, California
California ; Foraminifera ; Glacio eustatic change ; Isotope analysis ; Pleistocene ; Quaternary ; Sea level ; United States of America
The strontium isotopic compositions of foraminifers were determined to refine the age of coastal sediments of the Merced Formation and to evaluate the relation between transgressive-regressive cycles and Pleistocene glacio-eustatic sea-level

Sediment characterization and porewater isotope chemistry of Quaternary deposits from the St. Clair delta, Ontario, Canada

Sediment characterization and porewater isotope chemistry of Quaternary deposits from the St. Clair delta, Ontario, Canada
Canada ; Delta ; Fault ; Isotope analysis ; Ontario ; Quaternary ; Sedimentology ; Stratigraphy ; Wisconsinan
and porewater evolution using sedimentology, stable isotopes, and groundwater chemistry. This study will serve to assist the Walpole Island community in future land-use planning.

Carbon isotope composition of lake sediments in relation to lake productivity and radiocarbon dating

Carbon isotope composition of lake sediments in relation to lake productivity and radiocarbon dating
Canada ; Carbone ; Datation C 14 ; Géochimie ; Isotope ; Ontario ; Paléo-environnement ; Paléo-écologie ; Quaternaire ; Sédiment lacustre
C14 dating ; Canada ; Carbon ; Geochemistry ; Isotope ; Lacustrine sediment ; Ontario ; Paleo-ecology ; Paleo-environment ; Quaternary

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